Electrical connector assembly

ABSTRACT

An electrical receptacle and plug having means for automatically deenergizing the receptacle front whenever the plug is partially or wholly withdrawn therefrom. A one-piece coordinating plate carries a number of control fingers fixed thereon, thus assuring automatic and constant relative positioning of the control fingers. At least one finger prevents movement of the plate unless the plug is fully inserted. Movement of the coordinating plate automatically moves all control fingers simultaneously. When a power-control finger is moved towards a position which energizes the receptacle front, another finger engages the plug, locking the plug in the fully-inserted position. Movement of the plug-locking finger to the unlocked position automatically moves the power-control finger to the power-off position.

United States Patent [72] Inventors Arthur I. Appleton 2,986,612 5/1961 Healy ZOO/51.09 X Northbrook; 3,041,420 6/ 1962 Berry et a1 .....200/50.02 (UX) Namik 0. Atakkaan, Buffalo Grove; 3,263,037 7/ 1966 Correntl ZOO/51.09 X Duncan Turner, Jr., Desplaines, all of, III. 3,346,709 10/1967 Appleton ZOO/51.07 X 1969 Primary ExaminerDavid Smith, Jr.

d V d h Patenmd June Attorney Darbo, Robertson an an enburg [73] Assignee Appleton Electric Company Ch ABSTRACT: An electrical receptacle and plug having means for automatically deenergizing the receptacle front whenever 54 ELECTRICAL CONNECTOR ASSEMBLY the plug is partially or wholly withdrawn therefrom. A one- 6 chins, 38 Dn'ina m piece coordinating plate carries a number of control fingers fixed thereon, thus assuring automatic and constant relative [52] 0,8. Cl. zoo/B, positioning f the control fingem At least one finger prevents ZOO/5107 movement of the plate unless the plug is fully inserted. Move- [51] llll. Cl "01h 9/02 mam f h di i plate automatically moves a control- [30] Field of Search 200/5 1 .07- fingers Simultaneously w a powebcomml finger is moved 51, 50-2; 339/36'42 towards a position which energizes the receptacle front, 1 another finger engages the plug, locking the plug in the fully- [56] Re Cm inserted position. Movement of the plug-locking finger to the UNITED STATES PATENTS unlocked position automatically moves the power-control 2,441,465 5/ 1948 Bauroth ZOO/51.09 finger to the power-off position.

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PATENTEU JUN 1 5 Ian SHEET 05 0F .0 k 1 M 7 1 j A M 9 4 j Z M 7 q J21 d \/4 Hum W,||H:|.|| w flu y m a ,N N M mKN i2 rm R /U wM TA: MN h m PATENTEU JUN 1 51971 SHEET 10 [1F 11 ARTHUR f. APPLETO/V, NAM/K 0. ATAKKAAA/ ,5 puma/w TURNER J'R. ,fiwzglrmafil Electrical connector assembles comprising a receptacle and plug which permit the plug to be removed from the energized receptacle present a number of hazards. Exposed energized electrical contacts may cause personnel injury from electrical shock. An electrical arc which may occur when a plug is inserted intoor withdrawn from an energized receptacle may cause injury to personnel directly, may cause ignition of a flammable material inadvertently positioned closely adjacent thereto, may cause ignition of a flammable liquid, or flammable dusts of metal, carbon, or grain, and may cause an explosion in a hazardous area. Such connector assemblies can not be used in the areas'classified as hazardous because of the presence of combustible vapor, gas, dust or ignitable material.

One shortcoming of many of the so-called dead-face connector assemblies heretofore available has been the fact that it would be possible to inadvertently move'or shift the position of an exposed element, for example, by inadvertently pressing the face with a wrench or other metallic tool and thus inadvertently energize the portion in direct physical contact with the wrench or other tool. This shortcoming is believed inherent in virtually all of the heretofore available dead-face connector assemblies inwhich the face is energized by the insertion of the plug thereon;

This invention relates to electrical connector assemblies which provide a high degree of safety, inasmuch as it is impossible to reach energized components, or inadvertently energized externally exposed components whenever the plug is disconnected from the receptacle.

It is an object of this invention to provide an electrical connector assembly in which the exposed components are 100 percent nonenergized whenever the plug is partially or wholly disconnected from the receptacle. In the apparatus of this invention the face energizing function is separate from the depression of an insulating face plate. In this invention, the

face energizing function is inoperative unless the plug is completely inserted into the receptacle. It is a further object of this invention to provide a connector assembly in which it is impossible to disconnect the plug from the receptacle while the receptacle face isenergized. In this invention none of the means for accomplishing all the aforementioned functions are dependent upon electrical'energy of any sort for the maintaining of safe conditions whether the connector assembly is in the connected or disconnected condition. It is another object of this inventionto provide a receptacle and plug having'purely mechanical means for, (a) obtaining power-off conditions at the receptacle face whenever the plug is partially or wholly withdrawn therefrom, (b) for locking the plug into the receptacle only when the plug is fully inserted into the receptacle, and prior to the switching of switch means to the power-on condition, for continuing to lock the plug into the receptacle as long as the switch means are in the power-on condition, and, .(d) for positioning the switch means in the poweroff" condition prior to the unlocking of the plug.

SUMMARY OF THE INVENTION This invention relates to an electrical connector assembly having a dead-face receptacle.v The receptacle includes a mechanical programming element or plate, and means for locking out the programming element whenever the plug is partially or wholly withdrawn from the receptacle. The mechanical programming means automatically lock the plug from withdrawal prior to activation of switch means for energizing the receptacle face. Themechanical programming means also automatically operate switch means for deenergizing' the receptacle face before the plug is unlocked from withdrawal from the receptacle. In a preferred embodiment the means for unlocking the programming element is responsive to the final axial movement of the plug as it is inserted into receptacle, followed by manual rotation of the programming element around the axis.

2 DESIGNATION OF THE mum FIG. I is a partially cross-sectional view sectioned approximately throughv the middle of the substantially circular receptacle.

FIG. 2 is a partially cross-sectional view of the receptacle shown in FIG. 1 mated with a plug. The receptacle is shown in cross section to better illustrate the mating of the pieces.

FIG. 3 is a bottom view of the plug shown in FIG. 2.

FIG. 4 isa top view of the housing and-elements supported on the exterior of the housing.

FIG. 5 is a cross-sectional view taken approximately along the lines 5-5 in FIG. 9. I FIG. 6 is a crosssectional viewtaken approximately along the lines6-6 in FIG. 9. Y FIG. 7 is a cross-sectional view taken approximately along the line 7-7 of FIG. 4.

FIG. 8 is a cross-sectional 'view taken approximately along the line 8-8 ofFIG. 4. i

FIG. 9 is a cross-sectional view taken approximately along the line 9-9 of FIG. 4.

FIG. 10 is a cross-sectional view taken approximately along the line 10-10 of FIG. 9.

- FIG. 11 is a perspective view of the mechanical programming means for guaranteeing the proper sequence of steps of locking or unlocking the plug with respect to the receptacle and turning the power on or off.

FIG. 12 is a top view showing the programming means in position in the actuator ring.

FIG. 13 is a cross-sectional view taken approximately along the line 13-13 of FIG. 12.

FIG. 14 is a cross-sectional view taken approximately along the line 14-14 ofFIG. l3. i 3

FIG. 15 is a perspective view of the bolt of the automatic lock for immobilizing the programming means.

FIG. 16 is a schematic cross-sectional view illustrating the relative position of the programmer lock on the receptacle housing as viewed if the actuator ring were removed therefrom along with all of the programmer except for that portion thereof, shown in cross section, which engages the automatic lock.

FIG. 17 is the same view as shown in FIG. 16 in which the plug is shown fully inserted and the programmer has been rotated to the power-on" position.

FIG. 18 is a top view of the receptacle insulating face disc.

FIG. 19 is a bottom view of polarizing ring.

FIG. 20 is a perspective view of the insulating front block of the receptacle.

FIG. 21 is a bottom view of the insulating front block shown in FIG. 20.

FIG. 22 is a cross-sectional view of the insulating front block shown in FIG. 20 taken approximately along the lines 22-22.

FIG. 23 is a perspective view of the switch means rotor which resides within the lower portion of the front block shown in FIG. 20.

FIG. 24 is a cross-sectional view taken approximately along the line 24-24 of FIG. 23.

FIG. 25 is an enlarged fragmentary cross-sectional view taken along the line 25-25 of FIG. 26.

FIG. 26 is a cross-sectional view taken approximately along the line 26-26 of FIG. 2.

FIG. 27 is a cross-sectional view taken approximately along the line 227-27 of FIG. 2. FIG. 28 is a cross-sectional view FIG. 32 is an enlarged cross-sectional view taken approximately along the line '3 232 of FIG. 1.

' FIGL33 is an enlarged cross-sectional view taken approximately along the line 33-33 of FIG. 32.

FIG.'34, FIG. 35 and FIG. 36 are enlarged cross-sectional views as taken approximately along the line 34-34 of FIG. 32

showing the relative position of the rotor and rotor contact and the stationary line contact as the rotor moves'in the direction indicated by the arrow marked on.

FIG. 34 indicates the position at the start of the rotor motion. FIG. 35 shows the relative position of the components at that point in the rotor motion at which initial contact between the rotor contact and line contact occurs; it also represents the relative position of the components at thatpoint in the reverse rotor motion at which final contact precedes separation. FIG. 36 shows the relative position of the components when the rotor motion in the on direction is completed.

FIG. 37 is a view of a rotor contact bridge as viewed from the contact side.

FIG. 38 is a view of the rotor bridge contact as viewed from the rear or spring-abutting side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the following disclosure offered for public dissemination, in return for the grant of a patent, is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

This invention relates to a dead-face receptacle, generally 40, and mating plug, generally 41. Major components include a fixed receptacle housing 45, mechanical programming means 46, 46'; automatic programmer lock means, .generally 48, 48'; circumferential actuator ring 50; front insulating block, generally 51; switch-rotor 52; and circumferential plug lock slot 54.

ELEMENTS FIXED TO HOUSING 45 Front insulating block 51, is fitted with circumferential shoulder 56 which abuts shoulder 57 on housing 45. Block 51 is also provided with keying notches 58, which receive detent 59 in housing 45. Thus, shoulders 56 secure block 51 against motion in the direction of the axis of housing 45, while the mating of. notches 58 and detents 59 secure front block 51 from rotation about the axis of housing 45. Rotatably secured I in block 51 is line switch means, generally 61. The details of switch means'61 will be discussed hereinafter. Rear block 63, having line connectors 64 secured therein abuts the rearward end 67 of front block 51 and is secured from rotation about the axis by detent 68 in front block 45 (perhaps best seen in FIG. 21 and FIG. 31.) which also resides in elongated indent 69 in rotor.52. Retaining ring 70, is threaded around rear block 63 to seat on .aligned shoulders 72, 73, respectively, of rear block 63 and receptacle housing 45, respectively.

Though it is not shown in the drawing because it is not necessary for understanding the invention, it is preferred that, after line connection is made with line connectors 64, the connections be pottedin a permanent resin (not shown), such as epoxy, by filling well 75 formed by collar 76 with epoxy or some other suitable liquid, resinifiable material.

Mouth end' 80 of housing 45 is provided with outside threads 81 and a number of end notches 83 which function as part of the polarizing means. Receptacle face electrical connectors 85 are molded in place in front block 51. Thus passageways 89 do not represent openings that naturally exist in frdn't block'51 but rather indicate the extent of the insulating res'i'naroun'd face connectors 85 which are molded in place therein. However, passageway 88 is an actual opening.

Ground connector 86 is molded in place in rear block 63 and passes through the entire receptacle, first passing through elongated opening 87 in switch rotor 52 then through snugly fitting opening 88 in front block 51. Ground connector 86 is longer than face connectors to be the first to make, and last to break, contact.

Insulating faceplate, generally 90, is provided with four openings 91 oriented to loosely receive face. connectors85 and opening 92 to loosely receive ground connector 86.

Springs 94 positioned around connectors 85 keep insulating face plate away from front block 51. Insulating faceplate 90 is retained in position by abutment of'shoulder 96against opposing portion of polarizing ring 98 and retaining collar 99. Collar 99 is threaded on the inside to engage threads 81 on housing 45. Polarizing ring 98 is thus placed over the mouth end 80 of housing 45 with detent 101 (FIG. 19) residing in one of the notches 83, depending on the particular polarization desired. Retaining ring 99 is'threaded onto housing 45 'to secure polarizing ring 98 and insulating faceplate generally 90, in place therein. When collar 99'is threaded completely onto housing 45 polarizing ring 98. is incapable of rotation due to the residence of detents 101 in one of the notches 83. When polarizing ring 98 is thus immobilized, keying flange segments 102 and 103 thereof are thus fixed with respect to the position of front connectors 85. I

Plug, generally 41, includes main housing 105, flange 106, with a shoulder thereon insert end 107, and coupling ring 108. Ring 108 has threads 111 adapted to mate with outside threads 112 on ring 99. Insert end 107 of plug 41 is fitted with four circumferential key slots 102, 103', 113 and 114. Key slots 102' and 103' are positioned to mate with polarization ring detents 102 and 103 respectively, and moreover the position of female face connectors 91' and female ground connector 92' are so oriented that key slots 102 and 103' mate with polarization flange segments 102 and 103 when face connectors 91, 92 are mated with plug connectors 91' and 92' respectively. 1

By providing a number of slots 83 at the mouth 80 of housing 45 and a polarization ring 98 of the type illustrated, it is thus possible to provide for six polarization configurations using the same housing 45, and the same polarization ring 98. It is significant that polarization ring detents 101 are diametrically opposed to each other as are segments 102'and 103. It is also important in achieving twice as many polarization positions as notches 83, that the size of polarization segment 102 be substantially larger than polarization segment 103. End 80 of housing 45 is thus fitted in the illustrated embodiments with six notches 83, in .pairs of three positions diametrically opposite to each other at end 80 of housing 45. Thus, element 102 may be positioned in one of three locations on one side of the housing, or it may be positioned in any one of three positions on the other side of the housing, making it possible to build-in any one of six polarization configurations using the same housing 45 and same polarization ring 98 when there are three notches 83 on'each side of end 80 of housing 45. By the same token, if five such notches were provided, ten polarization configurations would be available, etc. Needless to say, retaining ring 99 is jammed or otherwise secured onto housing 45 during the course of manufacture to make it impossible to tamper with, or alter, the particular polarization configuration provided at the factory.

MECHANICAL PROGRAMMER A pair of identical one-piece sleeve segments, generally 46, (FIGS. 1114) serve as master programming elements to provide fool-proof control and assurance of proper relationship in the functional status of the various operating components of the connector of this invention.

Mechanical programmer, generally 46, is fittedv with three major control elements, namely, plug lock finger 115, which extends through slot 116 to the interior of housing 45; detent, or flange segment 118, which is slidably inserted into notches 119, 119' of housing 45; and line switch control cam 121, 121' which passes through slot 122 into the interior of housing 45. As perhaps bestseen in FIGS. 11 and 12, mechanical programming means 46, comprises a collar segment having outwardly beveled edges 124, and which key into recesses 125 in actuator ring 50. Programming means 46' is identical to programming means 46. Thus, in assembly, mechanical programming means 46, 46' are placed around housing 45 with control elements 115, 115', I18, 118', 121', extending into or through corresponding slots in housing 45. Thus, bottom edge 127 of programming means 46, 46' rests at shoulder 128 of housing 45 with concave face 129 of control elements 46, 46' being pressed against the external circumference of the housing 45. Actuator ring 50 is fittedover the mouth end 80, of housing 45 and down over housing 45 and over programming means 46, 46 which move into recessions 125, 125' thus becoming fixed with respect to rotation of the actuator. ring 50. When actuator ring 50 has been lowered over both housing 45 and programming means 46, 46' until bottom edge 130 of actuator ring 50 rests on shoulder 131 of housing 45, groove 133 positioned near shoulder 131 and ring 50 retain sealing means 134. Actuator ring 50, both maintains mechanical programming means 46, 46, in position against the external surface of housing 45, and moreover, fixes the position of mechanical programming means 46, 46' with respect to each other, i.e., diametrically opposite each other, and provides means for manually selecting positions of program means of 46, 46'. Thus, as perhaps best seen in FIGS. 5, 6 and 10, housing 45 is provided with linear perforations or slots 119, 122, and 116, respectively in pairs, each located diametrically opposite its respecti e counterpart as indicated by the nonprimed and primed numbers in FIGS. 5, 6 and 10, respectively.

PLUG LOCK MECHANISM As perhaps best appreciated from the consideration of FIGS. 2 and 3, only a plug having polarization slots 102 and 103', key slots 113, 114, female connectors 91' and female ground connector 92' will be received onto the receptacle, generally 40. Thus, as insertionof plug 41 into receptacle 40 brings locking finger 115 through key slot 113 as indicated by the arrow marked "A" in FIG. 2. The same occurrence takes place with respect to finger 115' in its corresponding key slot 114 on the opposite side of plug 41. Rotation of actuator 50 from this position, and with it control element 46, 46', moves locking fingers 115, 115' across into bayonet slot 54, as indicated by the arrow B" in FIG. 2.

Thus, plug 41 can not be locked into receptacle 40 unless and until plug 41 has been inserted to the point at which locking finger 115 is aligned with bayonet slot 54 and control means 46 and actuating ring 50 then is rotated to a lock position. Plug 41 can not be withdrawn unless and until actuator ring 50 is rotated to place locking finger 115 in withdraw slot 113.

AUTOMATIC PROGRAMMER LOCK Automatic programmer lock mechanism includes pin 137, stop 138, spring biasing means 139, and detent 118. Two identical lock mechanisms are used in the illustrated embodiment, and all parts in the second lock are numbered as herein described except that primed numbers are used. Spring biasing means 139 urges stop I38 upwardly to a first position, or look position, illustrated in FIG. 1 and FIG. 16. It is apparent that in this position, which prevails whenever plug 41 is either partially or wholly withdrawn from receptacle 40, stop 138 rests in alignment with slot 119 and leading edge 141 of detent 118 bears against stop 138. It is noted that lock supporting structure 143 does not extend into slot 119 to hinder the movement of detent 118 in slot 119, respectively. A second condition, or unlocked" position, of the automatic lock mechanism is illustrated in FIG. 2, 17 and 27. In this condition, which is obtained upon full insertion of plug 41 into receptacle 40, spring biasing means 139 are depressed, and stop 138 is lowered into enlarged portion which is positioned below the line of the bottom of slot 119, thus clearing slot 119 of any obstruction to the movement of detent 118.

Hence, whenever plug 141 is not fully inserted in receptacle 40, programmer lock means, generally 48, prevents any motion or change in position of programmer means 46, 46'. Pins 137 are not depressable by receptacle faceplate 90, but only plug 41, itself. This is assured since faceplate 90 includes recesses or passages 142 which permit complete depression of faceplate 90 with no engagement of pins 137. Hence, if faceplate 90 is advertently depressed, e.g., by a metallic tool, the lock is not released and the front can not be energized.

By providing a plurality of .pins 137 spaced apart from each other, in combination with a faceplate 90 having passages 142 aligned with pins 137 (FIG. 2), and in .combination with switch mechanism requiring depression of all pins 137 for energizing the receptacle front, inadvertent energizing of the front is rendered virtually impossible.

In the illustrated invention, moreover, the receptacle front is not automatically energized even when all pins are depressed. An additional step, namely, rotation of line switch mechanism, generally 61, is also necessary. Thus, it will be apby the illustrated embodiment.

LINE swircu MECHANISM The major components of the line switch mechanism 61 are perhaps best understood through a consideration of FIGS. 1, 28, 29, 30 and 31. The switch mechanism, generally 61, includes a pair of telescoping arms 147 which are biased outwardly by spring biasing means 148. Rollers 150, 150' are rotatably supported near the end of the telescoping arms 147. This structure is thus self-balancing. Radial forces exerted on wheels 150, 150 are necessarily equal, since they are at opposite ends of the same spring means 148.

Flat-headed shoulder bolts 152 retain telescoping arms 147 on hub 154 of shaft 155. Bolts 152 pass loosely through slot 156 in the telescoping arms 147. Bolts 152 permit movement of telescoping arms 147 in radial direction, even though they fix arms 147 and hub 154 with respect to rotational movement. Rotation of arms 147 thus causes rotation of hub 154 and shaft 155. Rotor 52 is secured to rotatable shaft by means of pin 157 and retaining spring (e.g., a C washer) 158. Pin 157 resides in slot 159, perhaps best seen in FIG. 24, to fix rotor 52 to shaft 155. Hence, rotation of shaft 155 and rotor 52'occur together.

Rotor 52 is provided with a plurality of upper and lower elongated depressions 161 and 162, respectively, in which front connector contacts 163 and line connector contacts 164, respectively, reside (see particularly FIG. 32). Contacts 163 and 164 are fixed with respect to receptacle 45. Contact bridges, generally 166, comprise a central support electrically conducting section 168, curved contact faces 169, 169', preferably made of silver, central spring-retaining post 171, and biasing spring 172. Contact bridges, generally 166, are passed through openings 174 at an angle and aligned so that the central support structure 168 abuts edge 175 of rotor 52 (FIG. 33). Bridges, 166, are urged against edge 175 due to the biasing effect of spring 172. Contact faces 169 are sufficiently wider than the corresponding dimension of opening 174 to prevent dropping of contact through opening 174. Thus, shoulders 177 slide along and rest upon the upper edges 179 of opening 174 of rotor 52.

As in the previously described systems, the line switch mechanism has two static positions, namely, the power-off position illustrated in FIGS. 28, 29, 32 and 34, and the power on position illustrated in FIGS. 30, 31 and 36. The entire rotor and contact system is maintained in the power-off position whenever rollers 150, 150' are on the power-off" side of the center 181 of control cam 121. It is noted that when wheels 150, 150' are not hearing against inclined surfaces 183, 184,

the outwardly biasing action of spring biasing means 148 forces brakes 186 located at the extreme ends of switch control means 61 against the interior wall of housing 45 thus preventing rotational motion in either direction.

Referring specifically to FIG. 28, clockwise rotation of actuating ring 50 causes clockwise rotation of mechanical programmer 46, 46', bringing inclined cam surfaces 183, 183' to bear against wheels 150, 150', respectively. It is noted that this action urges wheels 150, 150 in two ways: (a) in a clockwise direction thus urging rotor 52 against abutting stop 68 as seen in FIG. 29, and (b) radially toward the center of the mechanism. The radial movement lifts brake 186 from its contact with housing 45. As soon as clockwise rotation continues until wheels 150, 150' pass over-the-center.," the outwardly biasing action of spring bias means 148 drives the switch control mechanism, generally 61, in a counterclockwise direction as wheels 150, 150' roll down inclined surface 184. Switch control mechanism 61 comes to rest when the positions illustrated in FIGS. 30 and 31 are obtained, i.e., rotator 52 is urged against stop 68 at the other edge of slot 69, and detents of programmers 46, 46' come to a stop and are urged against the edge of their respective slots also.

Thus the outwardly biasing action of bias means 148 drives rotor 52 against stop 68, and drives both ends of each of the contact bridges, generally 166, against line and connector contacts 164 and 163, respectively.

As illustrated in FIGS. 33 through 36 contact bridge,

generally 166, abuts leading edge 175 of rotor 52 when the mechanism is in the power-off position. It is further noted that the leading edge 175 forms and angle (See FIG. 33) with the radius. Thus the entire bridge is carried on the bias, or at an angle, with respect to the radius, as perhaps best seen in FIG. 34, when the rotor is in the power-off condition. As the rotor rotates to the power-on. position, initial contact between curved contact 169 and flat-faced contacts 163, or 164, occurs at a point I as illustrated in FIG. 35. Continued rotation of rotor 52 to power-on position illustrated in FIG. 36, causes compression of spring bias means 172 and brings central support structure 168 away from leading edge 175. In the "power-off" position contact bridge, generally 166, floats against compression spring means 172. In the fraction of a second after contact at P,each bridge 166 rotates separately until curved faces 169, 169' comes to rest on flatfaces 163, 164 at P, as shown in FIG. 36.

Movement of rotor 52 in the reverse direction, i.e., in the counterclockwise direction to the power-off position first brings edge 175 against center support portion 168 causing each bridge structure 166 to pivot slightly until bridge 166 completely abutsleading edge 175 at which time the contacts between curved faces 169, 169' andfiat faces 163, 164 is then finally broken. Thus, it is seen that initial and final contact between the bridge contacts and the stationary contacts occurs at one point, namely P while the at rest contact point is a different point, namely, P,.. This particular configuration is extremely advantageous since arcing, and damage due to arcing at making and breaking of contact occurs at point P and the smooth separate rotation of the contact faces to abutment at point P, provides undamaged surfaces for the operational contacts.

OVERALL OPERATION OF RECEPTACLE AND PLUG mechanism, generally 48, out of abutment with face 141 of detent 118 on mechanical programmer 46. Complete insertion of plug 41 moves and keeps bolt 48 in enlarged portion 145, thus preventing lockout of programmer while plug is completely inserted. It is noted that until theplug is completely inserted edge 141 of detent 118 abuts bolt 138 (FIG. 16). Any operation of the mechanical programmer 46, 46', is automatically locked out whenever the plug is wholly or partially withdrawn.

When plug 40 is completely inserted, locking finger is opposite bayonet slot 54 in the wall of the mating portion of plug 41. Slight rotation of activating ring 50 also rotates programmer 46, 46', and carries locking finger ;115, 115 into bayonet slot 54, 54'. This is perhaps best illustrated in FIG. 2.

Thus, rotation of activation collar 50 from the insertion and withdrawal position, illustratedas Position 1 FIG. 28 -to Position 2 in FIG. 28, simply locks the plug to prevent withdrawal of the plug, and it does so beforeactivation'of the line switch means. In the preferred embodiment illustrated, the receptacle can be locked in any one of three positions by inserting a padlock through holes in a flange segment on the receptacle housing. Initial rotation of activating collar 50 in a clockwise direction to Position 2 in FIG. 28 carries detent 118, 118' over depressed bolt 138, 138' and brings inclined surfaces 183, 183' closer to wheels 150, 150', as locking finger 115 moves part way into bayonetslot 54 thus preventing withdrawal of plug 41 from receptacle 40. This rotation also brings collar stop-pin into groove 193 thus limiting further rotation of collar 50 to positions 2 and 3 unless collar stop-mechanism is released (stop-pin 191 elevated) thereby permitting rotation to Position No. 1.

As activating collar 50 is rotated in' clockwise direction from Position 2 to Position 3, locking finger 115 and detent 118 merely travel in their respective slots thereby leaving the status of their respective functions unchanged. Hence, the plug remains locked into the receptacle, while programming means 46, 46' continues to be free to be operated (unlocked)- However, continued rotation of collar 50 in a clockwise direction from Position 2 to Position 3 causes inclined surfaces 183, 183' to raise wheels-150, 150' over-the-counter" thereby causing the switch mechanism to snap abruptly to the "power-on" position described in detail above. While the receptacle programmer is in this position, it isimpossible to withdraw the plug from the receptacle, and lineconnections 64 and plug 41 are electrically connected. Rotation of activation collar 50 and programming means 46, 46' from Position 3 to Position 2 causes the switch mechanism to snap to the power-off" condition as hereinbefore described, and does so while keeping plug 41 locked in the fully inserted position. Stop 191 (FIG. 14) extending into a slot 192 (FIG. 4) prevents rotation of the activation collar to the insertion-withdrawal position indicated as Position 1 in FIG. 28. Moving tab 193 upwardly brings stop pin 191 out of slot 192 thus permitting rotation of collar 50 to the withdrawal-insertion" position (position 1, in FIG. 28) with the switching mechanism being in the power-off" condition. Nonetheless, rotation to the withdrawal position does not lock the programmer out of operation. That increment of rotation does position detent 118, and specifically leading edge 141 thereof,-past bolt 138, thus permitting elevation of bolt 138 into slot 119 by compression spring 139. While plug, generally 41, is fully inserted into receptacle, generally 40, bolt 138 resides in enlarged portion of slot 119, Le. in a nonobstructing position. However, at

this stage, locking finger 115 is now again aligned with slot 113, 113' thereby permitting withdrawal of the plug from the receptacle. But, only upon withdrawal of the plug from the receptacle, either partially or wholly, does the spring biasing means 139 of automatic programmer lock mechanism 48 move bolts 138 upwardly into the path of slot 119. Thus, any operation of the mechanical programmer is automatically locked out whenever, and only whenever, plug 41 iswholly or partially withdrawn from receptacle 40.

ACHIEVEMENT Thus, in accordance withthis invention all the objects set Y forth above are achieved. This invention provides a so-called dead-face" receptacle. of the type in which it is impossible to withdraw the plug whilethe face is energized. Moreover, this invention provides a receptacle in which the means for energizing the face is not directly responsive to the insertion of the plug, thus virtually, if not entirely, eliminating the risk of inadvertent energization of the facedue to the insertion or depression of a foreign object into the receptacle.

In accordance with this invention the complete insertion of the plug is required to unlock a separate mechanical faceenergizing switch system. This automatically guarantees the locking of the plug into the receptacle prior to energization of the face. The illustrated embodiment of this invention also automatically guarantees deenergizing of the face prior to unlocking of the plug from the receptacle. Moreover, special advances are achieved with respect to simplifying inventory required in order to achieve a large number of polarization configurations in receptacles. In addition, a substantial advance is shown with respect to improved switch mechanism contacts which assures that damaging arcing between contact surfaces does not occur at the point of operational contact.

Therefore we claim:

1. ln ad dead-front electrical receptacle and mating plug having receptacle connector and mating plug connector, the combination including: a receptacle including a housing having a neck with a circular portion thereof; and insulating front block supported by, and fixed with respect to, said housing, said block and said housing including means for supporting and maintaining said receptacle connector fixed with respect to said receptacle housing; contact pair comprising a line contact and a front .connector contact, said contact pair being fixed with respect to said housing; said pair being electrically connectable to each other through switch means, said connector contact being electrically connected to the receptacle connector; switch means for connecting and disconnecting said contact pair with respect to each other when said switch means are in an on" position and an off position respectively; control sleeve segment rotatably secured to said housing and being rotatable around said circular portion of said housing through a limited arc to a first and second position; biased sleeve-lock means for locking the position of the sleeve with respect to said housing, said sleeve-lock means being car ried by the housing, and including means for engaging the sleeve segment, said sleeve-lock means being biased to lock the sleeve against rotation from the first position, said sleevelock means including sleeve release means for releasing said sleeve-lock means, said sleeve release means being responsive to the plug when the plug is substantially fully inserted into the receptacle; plug-lock means for locking said plug against withdrawal from the receptacle, said plug-lock means per-' mitting complete entry of the plug into the receptacle when the control sleeve segment is in said first position, and including means for preventing withdrawal of the plug when the sleeve is in said second position; switch control means for moving said switch means to the on" position when the sleeve is rotated to said second position from said first position, and for moving said switch means to the off" position when the sleeve is rotated to said first position from said second position; said rotatable sleeve segment having fixed thereon means for operating said plug-lock means, and said switch control means; whereby the plug and receptacle cannot be separated while said sleeve is in said second position, in which position the receptacle front contact is electrically connected to the receptacle line contact, thereby making it impossible to expose the receptacle front when the receptacle connector is energized; whereby rotation of the control sleeve from the second position to the first position deenergizes the receptacle front connector and unlocks the plug to permit withdrawal of the plug from the receptacle; whereby the plug and receptacle can be separated, thereby exposing the receptacle front, when the sleeve is in said first position, in which position the receptacle connector is not electrically connected to the line contact; whereby upon withdrawal of the plugfrom the receptacle the sleeve is automatically locked against rotation whenever the plug is partially or wholly withdrawn, thereby making it impossible to energize the receptaclefront while the plug is partially or wholly withdrawn; and whereby complete insertion of the plug automatically releases the'control sleeve lock permitting the sleeve to be rotated from the first position to the second position thereby permitting the control switch means to be activated, and the receptacle front to be energized when the plug is wholly inserted.

2. The dead front electrical receptacle and mating plug of claim 1 in which the plug lock means includes a locking finger on said control sleeve and an L-shaped slot having a leg in the direction of the axis of the receptacle and a foot perpendicular to said leg in the circumference of the housing of the plug,

thereby the entire length of the leg of said slot moves over the locking finger during the insertion of the plug, and whereby rotation of the control sleeve moves the locking finer into the foot of the slot whereby preventing withdrawal of the plug until the locking finger is rotated back to the leg portion of the slot.

3. The dead front electrical receptacle and mating plug of claim 1 in which the switch control means includes a pair of said control sleeve segments and paired cam surfaces, said cam surfaces and said segments being positioned diametrically opposite each other in said receptacle, said cam surfaces being on said control sleeve segment, each of said cam surfaces tapering inwardly to a crown and thence outwardly; an overthe-center-mechanism including said cam surfaces, a telescoping slide extending across the diameter of the housing pivotally supported by said front block, means for limiting the pivoting of said slide through a limited arc, a pair of cam followers mounted at the ends of said telescoping slide, bias means for urging said cam followers outwardly, support means for maintaining said cam followers against said cam surfaces, and means for connecting said telescoping slide to said switch, the slide and the switch being pivotable to power-on and power-off" position; whereby-rotation of the control sleeve segment from said first position to said second position causes the telescoping slide to shorten as the inwardly inclined portion of the cam surface moves under the cam followers until the cam followers reach the peak connecting the inwardly and outwardly inclined cam surfaces, at which point the cam follower is biased outwardly along the outwardly inclined cam surface, the control sleeve being limited in its rotation to a point justbeyond the point at which the peaks pass under the cam followers, thereby causing the telescoping slide to pivot through an arc as the cam followers are urged down the outwardly inclined cam surface away from the peak to its on position, whereby the switch is also pivoted to its on position.

4. In the combination of a dead-front electrical receptacle member with a cylindrical body and mating plug member insertable into the receptacle member to an operative position, wherein one member has conductive prong parts and the other member has conductive socket parts to receive said prong parts, switch means in the receptacle for energizing said parts thereof, and plug securing means on the receptacle and movable to an effective position for releasably holding the plug in the operative position, the improvement comprising:

control means on said receptacle movable between an inactive position and an active position for moving said plug securing means to the effective position after said plug is in the operative position, for thereafter actuating said switch means to energize the parts on the receptacle member, and for actuating said switch means to deenergize the parts of the receptacle member before moving said plug securing means to an ineffective position, said control means including a ring surrounding said cylindrical body and rotatable with respect thereto between an inactive position and an active position, said body having arcuate openings therein, said ring having control ele ments extending through said openings to operate said switch means and said plug securing means. i

toward said operative position in the receptacle for moving the first part to the second position.

6. In the combination as set forth in claim 4, wherein one member has key slots and the other memberhas detents which mate therewith when the plug is in the operative position 'to prevent rotation of one member with respect to the other member.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 585, 323 Dated June 15, 197].

Inventor(s) Arthur I. Ap leton, Namik O. Atakkaan, Duncan Turner, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 5, "assembles" should read --assemblies-. Column 2, line 65, "227-27" should read 27-27-. Column 2, line 65, "Fig. 28" should start a new paragraph. Column 4, line 2 6, the comma after "106" should be deleted. Column 4, line 27, a comma should be inserted after "thereon" Column 5, line 9, after "118'," should be inserted l2l,. Column 5, line 74, "Fig." should read Figs.. Column 6, line 12, "advertently" should read inadvertently-. Column 6, line 42, after "in" should be inserted --a--. Column 7, line 14, the period after "center" should be deleted. Column 7, line 19, "rotator" should read --rotor. Column 9, line 22, "ad" should read --a-. Column 9, line 26, "and" should read --an-. Column 10, line 16, "finer" should read --finger-. Column 10, line 17, "whereby" should read thereby. Column 10, line 26, "segment" should read -segments.

Signed and sealed this 6th day of February 1972.

(SEAL) Attest:

EDWARD M.FLETCHER ,JR BERT GOTTS CH ALK Attesting Qffi er Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 60375. :159

U 5 GOVERNMENT PRINTING OFFICE 1 IPIF O3CQ-l3l 

1. In ad dead-front electrical receptacle and mating plug having receptacle connector and mating plug connector, the combination including: a receptacle including a housing having a neck with a circular portion thereof; and insulating front block sUpported by, and fixed with respect to, said housing, said block and said housing including means for supporting and maintaining said receptacle connector fixed with respect to said receptacle housing; contact pair comprising a line contact and a front connector contact, said contact pair being fixed with respect to said housing; said pair being electrically connectable to each other through switch means, said connector contact being electrically connected to the receptacle connector; switch means for connecting and disconnecting said contact pair with respect to each other when said switch means are in an ''''on'''' position and an ''''off'''' position respectively; control sleeve segment rotatably secured to said housing and being rotatable around said circular portion of said housing through a limited arc to a first and second position; biased sleeve-lock means for locking the position of the sleeve with respect to said housing, said sleevelock means being carried by the housing, and including means for engaging the sleeve segment, said sleeve-lock means being biased to lock the sleeve against rotation from the first position, said sleeve-lock means including sleeve release means for releasing said sleeve-lock means, said sleeve release means being responsive to the plug when the plug is substantially fully inserted into the receptacle; plug-lock means for locking said plug against withdrawal from the receptacle, said plug-lock means permitting complete entry of the plug into the receptacle when the control sleeve segment is in said first position, and including means for preventing withdrawal of the plug when the sleeve is in said second position; switch control means for moving said switch means to the ''''on'''' position when the sleeve is rotated to said second position from said first position, and for moving said switch means to the ''''off'''' position when the sleeve is rotated to said first position from said second position; said rotatable sleeve segment having fixed thereon means for operating said plug-lock means, and said switch control means; whereby the plug and receptacle cannot be separated while said sleeve is in said second position, in which position the receptacle front contact is electrically connected to the receptacle line contact, thereby making it impossible to expose the receptacle front when the receptacle connector is energized; whereby rotation of the control sleeve from the second position to the first position deenergizes the receptacle front connector and unlocks the plug to permit withdrawal of the plug from the receptacle; whereby the plug and receptacle can be separated, thereby exposing the receptacle front, when the sleeve is in said first position, in which position the receptacle connector is not electrically connected to the line contact; whereby upon withdrawal of the plug from the receptacle the sleeve is automatically locked against rotation whenever the plug is partially or wholly withdrawn, thereby making it impossible to energize the receptacle front while the plug is partially or wholly withdrawn; and whereby complete insertion of the plug automatically releases the control sleeve lock permitting the sleeve to be rotated from the first position to the second position thereby permitting the control switch means to be activated, and the receptacle front to be energized when the plug is wholly inserted.
 2. The dead front electrical receptacle and mating plug of claim 1 in which the plug lock means includes a locking finger on said control sleeve and an L-shaped slot having a leg in the direction of the axis of the receptacle and a foot perpendicular to said leg in the circumference of the housing of the plug, thereby the entire length of the leg of said slot moves over the locking finger during the insertion of the plug, and whereby rotation of the control sleeve moves the locking finer into the foot of the slot whereby preventing withdrawal of the plug until the locking finger is rotated back to the leg portion of the sLot.
 3. The dead front electrical receptacle and mating plug of claim 1 in which the switch control means includes a pair of said control sleeve segments and paired cam surfaces, said cam surfaces and said segments being positioned diametrically opposite each other in said receptacle, said cam surfaces being on said control sleeve segment, each of said cam surfaces tapering inwardly to a crown and thence outwardly; an over-the-center-mechanism including said cam surfaces, a telescoping slide extending across the diameter of the housing pivotally supported by said front block, means for limiting the pivoting of said slide through a limited arc, a pair of cam followers mounted at the ends of said telescoping slide, bias means for urging said cam followers outwardly, support means for maintaining said cam followers against said cam surfaces, and means for connecting said telescoping slide to said switch, the slide and the switch being pivotable to ''''power-on'''' and ''''power-off'''' position; whereby rotation of the control sleeve segment from said first position to said second position causes the telescoping slide to shorten as the inwardly inclined portion of the cam surface moves under the cam followers until the cam followers reach the peak connecting the inwardly and outwardly inclined cam surfaces, at which point the cam follower is biased outwardly along the outwardly inclined cam surface, the control sleeve being limited in its rotation to a point just beyond the point at which the peaks pass under the cam followers, thereby causing the telescoping slide to pivot through an arc as the cam followers are urged down the outwardly inclined cam surface away from the peak to its ''''on'''' position, whereby the switch is also pivoted to its ''''on'''' position.
 4. In the combination of a dead-front electrical receptacle member with a cylindrical body and mating plug member insertable into the receptacle member to an operative position, wherein one member has conductive prong parts and the other member has conductive socket parts to receive said prong parts, switch means in the receptacle for energizing said parts thereof, and plug securing means on the receptacle and movable to an effective position for releasably holding the plug in the operative position, the improvement comprising: control means on said receptacle movable between an inactive position and an active position for moving said plug securing means to the effective position after said plug is in the operative position, for thereafter actuating said switch means to energize the parts on the receptacle member, and for actuating said switch means to deenergize the parts of the receptacle member before moving said plug securing means to an ineffective position, said control means including a ring surrounding said cylindrical body and rotatable with respect thereto between an inactive position and an active position, said body having arcuate openings therein, said ring having control elements extending through said openings to operate said switch means and said plug securing means.
 5. In the combination as set forth in claim 4, including locking means on said receptacle member and having a first part movable between a first position at which said ring is blocked at the inactive position and a second position at which said ring is free to move from the inactive to the active position, said locking means being urged to the first position and having a second part connected to the first part and positioned to be contacted by the plug member as the latter is moved toward said operative position in the receptacle for moving the first part to the second position.
 6. In the combination as set forth in claim 4, wherein one member has key slots and the other member has detents which mate therewith when the plug is in the operative position to prevent rotation of one member with respect to the other member. 